Is that part of the Firefox Browser and not a Addon?

I did this accidentally via FB to block a horrible spam going around- thinking I was just blocking that one post/story. It now won't let me edit anything on my FB page on my desktop computer. I know it is Firefox related as my FB works on other browsers. I also asked this question and never received any answers. I believe it's a right click option within Firefox. I would like to know how to reverse blocking this element.